Fresh water supply system for a railway vehicle

ABSTRACT

A fresh water supply system for a railway vehicle has a fresh water tank, a feed line extending from the fresh water tank for fresh water consumers to be supplied, and a valve that is located within the feed line for metered dispensing of fresh water. The valve is disposed at a lower level than a fresh water outlet of the fresh water tank. A pressure sensor is disposed upstream of the valve and it has a signaling connection to an evaluation unit. Typical characteristic pressure values for the fresh water supply system are stored in the evaluation unit and the evaluation unit detects discrepancies between the characteristic pressure values and the pressure values supplied by the pressure sensor. From this, a fill level of the fresh water tank and/or a flow velocity of the fresh water are estimated.

The invention relates to a fresh water supply system for a rail-borne vehicle, said fresh water supply system having a fresh water tank, a supply line that leads out of the fresh water tank for the purpose of supplying consumers of fresh water, and a valve that is provided in the supply line that is provided for the purpose of dispensing fresh water in a metered manner and said valve is arranged at a lower level than a fresh water outlet of the fresh water tank.

A fresh water supply system of this type is primarily used in the case of regional trains and high speed trains. A fresh water tank is generally arranged in the roof region of the train. The supply line that leads out of the fresh water outlet of said fresh water supply system supplies fresh water by way of example to sanitation systems such as a toilet or a water outlet for a hand wash system. In the two examples, fresh water is dispensed in a metered manner with the aid of a respective valve that is arranged below the fresh water outlet.

It is known from the prior art to provide dedicated sensors for the freshwater tank, in particular a float sensor that outputs a fill level of the fresh water tank in order to monitor the availability of fresh water. With regard to dispensing fresh water in a metered manner to the consumers that are to be supplied there are no hitherto known procedures that render it possible to dispense uniform amounts of fresh water. It is difficult to dispense uniform amounts of fresh water because while the fresh water system is in use it is possible by way of example for the supply line and/or filters that are provided to become contaminated so that, when the valve is open for a uniform period of open time, a flow rate of the fresh water in the supply line that is reduced as a result of the contamination delivers a reduced amount of fresh water.

Furthermore, an amount that is dispensed also depends on the prevailing fill level of the fresh water tank.

It follows from this that the object of the invention is to further develop the fresh water supply system mentioned in the introduction in such a manner that an amount of fresh water that is dispensed by the valve remains essentially uniform at least within specific thresholds during one period of time.

This object is achieved by virtue of the fact that a pressure sensor is provided upstream of the valve and said pressure sensor is connected to an evaluating device in such a manner as to be able to provide signals and said evaluating device stores pressure characteristic values that are typical for the fresh water supply system and the deviations between the pressure characteristic values and the pressure values that are provided by the pressure sensor for the purpose of estimating a fill level of the fresh water tank and/or a flow rate of the fresh water are determined.

It is possible with the aid of the pressure sensor to monitor both a fill level of the fresh water reservoir and also a flow rate of the fresh water in the supply line. Since the valve is arranged at a lower level than the fresh water outlet of the fresh water reservoir, a hydrostatic pressure on an input side of the valve can be measured with the aid of the pressure sensor. A prevailing fill level of the fresh water tank can be deduced from said hydrostatic pressure measurement. When the fresh water is flowing, the pressure sensor renders it possible to determine a flow rate of the fresh water in the supply line as a result of the pressure measurement values that are provided to said pressure sensor by said flowing fresh water in particular in the case of a drop in pressure that occurs while the valve is open. As a consequence, the fresh water supply system is suitable for the purpose of considering relevant values, namely the fill level of the fresh water tank and/or the flow rate of the fresh water in the supply line in order to dispense an amount of fresh water so that where necessary it is possible to influence the period of time that the valve remains open.

The evaluating device preferably determines whether the valve is open or closed and said evaluating device determines from the values that are provided by the pressure sensor in the case of an opened valve the deviation of said values with respect to the pressure characteristic values for the fresh water supply system in the cleaned state and said evaluating device determines from the values that are provided by the pressure sensor in the case of a closed valve the deviation of said values with respect to the pressure characteristic values for a completely filled fresh water tank.

If by way of example minimum values for deviations between the measured pressure values and the pressure characteristic values are achieved, procedures can be performed such as refilling the fresh water tank or cleaning the supply lines of the fresh water supply system.

The pressure sensor can be arranged directly upstream of the valve so that a pressure that prevails at the valve inlet side can be measured as precisely as possible.

In the case of the evaluating device calculating the fill level of the fresh water reservoir, said fill level value can be additionally output so that the fresh water tank can be filled as required.

Since the pressure sensor is suitable for establishing a fill level of the fresh water tank, the fresh water tank does not require dedicated fill level sensors. It goes without saying that it is possible for said fresh water tank to use a dedicated fill level sensor despite the presence of the pressure sensor.

The evaluating device can in addition function as a control device for the valve, wherein said evaluating device controls the valve in such a manner that, irrespective of a fill level of the fresh water tank, an amount of fresh water that is dispensed remains essentially uniform by means of varying the opening time of the valve. The measurement of the flow rate of the fresh water can also be evaluated to the effect that a degree of contamination in the supply line is determined from calculated values for the flow rate.

As a consequence, cleaning procedures in particular for the supply line and filters can be performed.

Exemplary embodiments of the invention are further explained herein under with reference to the drawing, wherein components with identical functions are described with like reference numerals. In the drawings:

FIG. 1 illustrates a schematic illustration of a fresh water supply system for a rail-borne vehicle in a first embodiment, and

FIG. 2 illustrates a schematic illustration of a fresh water supply system for a rail-borne vehicle in a second embodiment.

A reservoir of fresh water is already provided in a fresh water tank 1 for the purpose of supplying fresh water in a rail-borne vehicle. The fresh water can leave the fresh water tank 1 by way of an outlet 8 that is provided on the base of said fresh water tank and said fresh water travels out from there initially to a water filter 4. Downstream of the water filter 4, the pipe system branches out in the direction of a solenoid valve 2 and also in the direction of a toilet (not illustrated) that is reached by means of a supply line 5.

In the present exemplary embodiment, the solenoid valve 2 is associated with a water outlet (tap) 3 for a hand wash system.

Directly upstream of the solenoid valve 2, the supply line 9 that is located directly upstream of the solenoid valve 2 and that extends to the outlet 8 is equipped with a pressure sensor 6 that is connected to the interior of a pipe section upstream of the solenoid valve 2 and provides measurement values for the prevailing pressure at said pipe section.

The measurement values that are provided by the pressure sensor 6 are supplied to a control device 7 that is connected to the solenoid valve 2 in such a manner as to be able to control said solenoid valve.

The control device 7 determines whether the solenoid valve 2 is open or closed. If the solenoid valve 2 is closed, the pressure sensor 6 measures the prevailing hydrostatic pressure at the measuring site and the control device 7 calculates from this measured value a fill level of the fresh water tank. Said calculation is possible because the measuring site of the pressure sensor 6 is arranged at a lower level than the water outlet 8 of the fresh water tank 1.

If the control device 7 establishes that the solenoid valve 2 is open, it is possible with the aid of the measurement values that are delivered by the pressure sensor 6, in particular by way of the drop in pressure that occurs while the valve is open, to determine a flow rate of the fresh water that prevails in the associated pipe. This flow rate indicates to what extent possible obstructions and contamination are present upstream of the measuring site. In particular it is also possible to determine by way of the pressure values the state of the water filter 4, in other words to what extent said water filter is contaminated.

It is possible by means of a characteristic value stored in the control device 7 to consider both the fill level in the fresh water tank 1 and also a degree of impairment as a result of contamination in the supply line 9 or rather the water filter 4 in order to provide an essentially uniform amount of fresh water to the water outlet 3. If by way of example the fill level of the fresh water tank 1 decreases or rather a degree of contamination in the water filter 4 or the pipe that is located in this region increases, it is possible with the aid of the control device 7 to suitably extend the period of time that the solenoid valve 2 is open so that a uniform amount of water is provided at the water outlet 3.

In exemplary embodiments that are designed in a simpler manner, the control device can also only function as an evaluating device and can calculate and output values for a fill level of the fresh water tank 1 or rather for the flow rate in the region of the measuring site of the pressure sensor 6. As a consequence, a suitable procedure can be performed where necessary manually on the basis of said values. Procedures of this type are by way of example refilling the fresh water tank 1 or cleaning the water filter 4.

The exemplary embodiment according to FIG. 2 differs from that according to FIG. 1 primarily by means of the arrangement of the pressure sensor 6. While the pressure sensor 6 in the case of the exemplary embodiment according to FIG. 1 is located on a piece of pipe of the supply line 9 that is arranged between the solenoid valve 2 and the water filter 4, the pressure sensor 6 in the case of the exemplary embodiment according to FIG. 2 is arranged in the supply line 9 directly upstream of the water filter 4. The functionality of the two exemplary embodiments that are illustrated in the figures is otherwise identical.

The embodiment according to FIG. 1 is particularly suitable for determining a degree of contamination in the supply line 9. The embodiment according to FIG. 2 is characterized by virtue of the fact that it renders it possible to reliably measure a fill level of the fresh water tank. 

1-6. (canceled)
 7. A fresh water supply system for a rail-borne vehicle, the system comprising: a fresh water tank having a fresh water outlet; a supply line leading away from said fresh water tank for supplying a consumer with fresh water; a valve in said supply line for dispensing fresh water through said valve, said valve being arranged at a lower level than said fresh water outlet of said fresh water tank; a pressure sensor disposed upstream of said valve and configured to measure a pressure in said supply line upstream of said valve; and an evaluating device connected to said pressure sensor for receiving measurement signals with pressure values; said evaluating device storing pressure characteristic values that are typical for the fresh water supply system and determining deviations between the pressure characteristic values and the pressure values received from said pressure sensor and estimating therefrom at least one or both of a fill level of the fresh water tank or a flow rate of the fresh water.
 8. The fresh water supply system according to claim 7, wherein: said evaluating device is configured to determine whether said valve is open or closed; said evaluating device is configured to determine from the pressure values received from said pressure sensor in case of an open valve the deviation of said values with respect to the pressure characteristic values for the fresh water supply system in the cleaned state; and said evaluating device is configured to determine from the pressure values received from said pressure sensor in case of a closed valve the deviation of said values with respect to the pressure characteristic values for a completely filled fresh water tank.
 9. The fresh water supply system according to claim 7, wherein said pressure sensor is arranged directly and immediately upstream of said valve.
 10. The fresh water supply system according to claim 7, wherein said evaluating device is configured to calculate and output the fill level of said fresh water tank.
 11. The fresh water supply system according to claim 7, wherein said fresh water tank does not require dedicated fill level sensors.
 12. The fresh water supply system according to claim 7, wherein said evaluating device is configured to also function as a control device for said valve, and wherein said control device controls said valve such that, irrespective of a fill level of said fresh water tank, an amount of fresh water that is dispensed remains substantially uniform by varying a period of time that the valve remains open. 